Major airports are frequently constructed to have large-capacity underground supply systems for aircraft fuel. Access to the supply systems is by way of hydrants located below the airport surface but accessible from the surface of the airport. The hydrants are equipped with flow-control valves whose open and closed positions are controlled by pressurized air supplied to the valve by a pneumatic hose under the control of the operator of the refueler vehicle.
A refueler vehicle of the hydrant type is not equipped with a refueling tank. The essential elements of a hydrant refueler vehicle are: a fuel hydrant hose and means for coupling the fuel hydrant hose to the hydrant; a pressurized air hose controllable by the refueler operator from a remote position, such as at the fuel intake valve of the aircraft and means for coupling the pressurized-air hose to the hydrant valve; at least one, and preferably two or more, fuel delivery hoses and means for coupling the fuel delivery hoses to the intake valve(s) of the aircraft; means, usually including filtering means and metering means, inter-connecting the hydrant and delivery fuel hoses on the refueler vehicle; and at least one platform or deck for supporting the operator as he connects the fuel delivery hose(s) of the refueler vehicle to the intake or tank valve(s) of the aircraft usually located on the undersurface of one of the wings of the aircraft. No fuel pump is needed on a hydrant refueler vehicle. Pressure for causing the fuel to flow from the underground supply system into the tanks of the aircraft is provided by the underground supply facilities at the airport.
To accommodate for different models of aircraft having wings at different heights above ground, it is customary for the refueler vehicles, whether of the hydrant type or of the tank type, to be equipped with an elevator platform on which the operator stands when he makes the connection of the delivery fuel hose(s) to the tank valve(s) on the underside of the aircraft wing and also during subsequent delivery of the fuel into the aircraft tank(s). Such elevator platform may, for example, be of the scissors type. However, an elevator platform, whether of the scissors or other type, has the undesirable feature of tending to become jammed or otherwise disabled, particularly in sub-freezing weather when ice collects on the equipment. When this occurs, take-off of the plane may be delayed. This concludes a brief discussion of the background of the present invention.
Pertinent prior patent art of which we are aware is U.S. Pat. No. 2,525,074, issued Oct. 10, 1950, to J. E. Knight. This patent shows an elevatable platform.
Pertinent prior publication art is a publication of General Transervice Inc., a subsidiary of Watkins Systems to which the present invention is assigned. This publication shows a fixed platform, foldable guard railings and loose cross-guard chains.
Pertinent physical prior art is a Rampmaster Modular Refueler for which General Transervice Inc. is exclusive distributor. This vehicle had a two-level fixed deck, fold down guard railings, and loose chain cross-guards.